CYFLUTHRIN APPLIED WITH AND WITHOUT PIPERONYL BUTOXIDE AND PIPERONYL BUTOXIDE PLUS CHLORPYRIFOS-METHYL FOR PROTECTION OF STORED WHEAT

Soft red winter wheat treated with 0.5, 1.0, 1.5, or 2.0 ppm cyfluthrin, all rates + 8.0 ppm piperonyl butoxide, and all rates with piperonyl butoxide + 6.0 ppm chlorpyrifos-methyl was stored for 10 mo at ambient conditions in southern Georgia. Samples of wheat were bioassayed with lesser grain barer, Rhyzopertha dominica (F.), and rice weevil, Sitophilus oryzae (L.), every 2 mo. Lesser grain borer survival on wheat treated with cyfluthrin alone ranged from 0-37.0%, whereas survival in the cyfluthrin + piperonyl butoxide and cyfluthrin + piperonyl butoxide + chlorpyrifos-methyl combinations ranged from 0 to 16.0%. No F-1 adults or ground flour (dockage) was present in incubated samples. Rice weevil survival on wheat treated with 0.5 and 1.0 ppm cyfluthrin steadily increased to a maximum of 94.5 and 43.5%, respectively, after 10 mo. Survival was reduced on wheat treated with 1.5 and 2.0 ppm cyfluthrin, and beetles did not survive in the piperonyl butoxide-chlorpyrifos-methyl combinations. The number of F-1 rice weevils and the amount of dockage were greatest in the two lowest rates of cyfluthrin. F-1 adults and dockage weight were positively correlated with initial survived.